With respect to water purification systems of the type that utilize a venturi device in order to effect mass transfer of gasses or liquids into a stream of water, it is well known that such venturi devices will operate well only within a predefined pressure differential of the motive fluid stream. For instance, where ozone is developed by an ozone generator, the ozone may be drawn through a venturi injector/mixer in order to mix the ozone with the water. In this instance, it is well known that bubble size of the ozone is critical in transferring a requisite amount of ozone into the water to effect purification thereof. If the ozone bubble size is too large, the ozone will not have an opportunity to dissolve in the water, and will be lost. Conversely, the smaller the ozone bubble size the better mass transfer of ozone will occur into the water.
One problem with the venturi injector/mixers on the market today is that while they work satisfactorily to develop a small bubble size within a relatively narrow pressure differential range, when the pressure differential is increased above this range the bubble size also increases, resulting in decreased mass transfer of the ozone. As such, in systems where the pressure differential varies widely, such as in cooling towers and water cooled systems utilizing gravity fed outdoor tanks wherein a water level in the tanks varies within a wide range, transfer of ozone into the water will also vary widely. This is particularly a problem in view the recent discovery that bacteria that cause Legionnaires disease tend to colonize in larger organisms, such as amoebas, which are more resistant to lower levels of ozone, but which are killed by consistently higher levels of ozone, particularly in combination with chemical sanitizers. Additionally, consistent levels of ozone are known to kill cryptosporidium, a particularly resistant organism that may be fatal to those with weakened or otherwise compromised immune systems.
In other situations, such as swimming pools and spas, variations in design of the different manufacturers of swimming pools and spas and the different accessories associated with each individual pool or spa lead to situations where a particular venturi injector/mixer that works well on one pool may not work well on an identical pool fitted with an additional or different accessories, such as a water heater. In this instance, a different venturi must be custom fitted or the original venturi modified in accordance with the different available pressures and flow rates. Further, the pressure differential across the filter and other accessories in some pools is not high enough to power a venturi injector/mixer, leading to the requirement of a valve in the line after the pump, with the venturi inlet installed upstream from the valve and downstream from the pump. This valve is partially closed to develop the required pressure across the venturi injector/mixer, which in turn has a deleterious effect on seals in the pump and generally shortens life of the pump. Where the valve is located after the filter, then the filter may also be adversely affected by these higher pressures.
Accordingly, it is one object of the invention to provide a venturi injector/mixer having a variable injection/suction opening that is smaller with a lower inlet pressure and which increases in size with increasing pressure. Other objects will become apparent upon a reading of the following specification.